In spite of the recent striking technical improvements in the medical field, many problems remain unsolved. The problem of myocardiopathy is one of the important unsolved subjects.
Myocardiopathy is a general name for diseases attributable to organic and functional abnormalities of the cardiac muscle. For example, cardiomyopathy is classified into secondary cardiomyopathy, which occurs in sequence to hypertension, dysbolism, ischemic disease and such, and idiopathic cardiomyopathy (ICM), which occurs without any distinct fundamental disease. Hypertrophic cardiomyopathy (HCM) is classified as an ICM, whose cause of disease is most revealed at the genetic level. In half the numbers of patients which HCM, familial history following autosomal dominant heredity is recognized. Linkage analysis of such family lines, with multiple patients as the object, revealed 5 causal loci so far and the causal gene itself is specified in 4 of them.
Many cases of dilated cardiomyopathy (DCM) occur independently, but familial history is recognized in 20% of the cases. Linkage analysis of such family lines, with multiple patients as the object, revealed 7 types of causal loci (causal genes are unknown).
Regarding myocardiopathy, research is in progress to specify causal gene and to reveal the mechanism underlying the start of disease. So far, no concrete action for gene therapy has been done.
On the other hand, the rapid progress lately in molecular biology has made is possible to activate cellular function by gene transfer methods and various attempts have been made. In particular, there are some reports for gene transfer methods to the heart, like intravenous drip (J.Clin.Invest., 90, 626–630 (1992)), direct injection (Circulation, 82, 2217–2221 (1990); Circulation, 90, 2414–2424 (1994)) or coronary diffusional infusion method that utilizes the plasmid as it is (J.Thorac.Carduivasc.Surg., 109, 716–720 (1995)) and so on, but were far from noninvasive concrete treatment.